This thesis covers two topics in the Generalized Vector Dominance
Model. In the first topic we construct a model for dilepton production
in hadron·hadron interactions based on the idea of generalized vectordominance.
We argue that in the high-mass region the generalized vectordominance
model and the Drell-Yan parton model are alternative descriptions of the same underlying physics. In the low-mass regions the models
differ; the vector-dominance approach predicts a greater production of
dileptons. We compare the model to the limited dilepton data that are
presently available and also integrate over one of the leptons to study
the contributions to the single-lepton yield. Without the benefit of
some very recent data we find that the high-mass vector mesons which are
the hallmark of the generalized vector-dominance model make little contribution
to the large yield of leptons observed in the transverse-momentum
range 1 < p .< 6 GeV. The recently measured hadronic parameters
lead one to believe that detailed fits to the data are possible under
our model. The possibility was expected, and we illustrate with a simple
model the extreme sensitivity of the large-p lepton yield to the 1arge-
transverse-momentum tail of vector-meson production.
The second topic is an attempt to explain the mysterious phenomenon
of photon shadowing in nuclei utilizing the contribution of the 10ngitudinally
polarized photon. We argue that if the scalar photon antishadows,
it could compensate for the transverse photon, which is presumed
to shadow. We find in a very simple model that the scalar photon
could indeed anti-shadow. The principle feature of our model is a cancellation
of amplitudes. The scheme is consistent with scalar photonnucleon
data as well. We test our idea with two simple GVDM models and
find that the anti-shadowing contribution of the scalar photon is not
sufficient to compensate for the contribution of the transverse photon.
We find it doubtful that the scalar photon makes a significant contribution
to the total photon-nuclear cross section.